Feeding sensor of quantitative control for die caster

ABSTRACT

A feeding sensor for die caster comprises a storage tank storing molten metal, a positioning member atop the storage tank, a feeding pipe connected to the positioning member and having one end passing through an opening of the storage tank and placed below a surface of the molten metal. A container of fixed volume is connected to another end of the feeding pipe and has a control valve and an air pump. A columnar supporting post has one end connected to the feeding pipe and another end connected to a weight sensor.

FIELD OF THE INVENTION

[0001] The present invention relates to a feeding sensor of quantitative control for a die caster, especially to a feeding sensor for a die caster, which can precisely measure the net weight of casting metal such as Mg.

BACKGROUND OF THE INVENTION

[0002] For die casting some metal such as magnetism, the injected amount should be precisely controlled. Therefore, it is advantageously to provide a storage space at certain location of the transmission duct to store molten metal of fixed amount and then the stored metal is sent in batch to a die for casting. FIGS. 1 and 2 show a conventional die caster, which has a storage tank la containing molten metal 2 a. The storage tank la can also be a high-temperature furnace. A feeding pipe 3 a passes through a top opening of the storage tank la and with an inlet end thereof being below the surface of the molten metal. An outlet end of the feeding pipe 3 a is connected to a container 7 a of fixed volume. A one-way valve 31 a is arranged at the inlet end of the feeding pipe 3 a. The container 7 a is provided with a control valve 9 a connected to bottom of the container 7 a through a connection pipe 92 a, and an air pump 8 a. As shown in FIG. 1, the air pump 8 a initially drains air out of the container 7 a such that the molten melt 2 a continuously flows into the container 7 a until a fixed amount of the molten melt 2 a is stored in the container 7 a. At this time, the air pump 8 a stops draining air out of the container 7 a. As shown in FIG. 2, the air pump 8 a then starts drawing air into the container 7 a and a piston 91 a is pushed, whereby the molten melt 2 a flows into a casting die (not shown) through an exiting pipe 93 a. In above arrangement, the air pump 8 a drains an inert gas out of the container 7 a or draws an inert gas into the container 7 a to prevent oxidation of the container 7 a.

[0003] To provide quantitative control over the molten melt 2 a, a sensing stick 70 a is provided in the container 7 a and has a sensor (not shown) thereon. The position of the sensor on the sensing stick 70 a determined a desired amount of the molten melt 2 a in the container 7 a. The injected amount of the molten metal 2 a is related to the position of the sensor. Therefore, the sensor is generally in contact with the molten metal 2 a and has the risk of damage or deterioration. Moreover, the designated amount of the molten melt 2 a may be modified for different dies, the amount of the injected molten melt 2 a is obtained with empirical curve with suitable calibration, in case that the same sensing stick 70 a is repeatedly used. The detection accuracy is influenced.

SUMMARY OF THE INVENTION

[0004] It is the object of the present invention to provide a feeding sensor of quantitative control for a die caster, which is arranged externally instead of being within the container. The feeding sensor of quantitative control can precisely measure the weight of molten metal even though different amount of molten metal is set. Therefore, the maintenance cost and the manufacture cost are reduced.

[0005] To achieve above object, the present invention provides a feeding sensor for die caster comprising a storage tank storing molten metal, a positioning member atop the storage tank, a feeding pipe connected to the positioning member and having one end passing through an opening of the storage tank and placed below a surface of the molten metal. A container of fixed volume is connected to another end of the feeding pipe and has a control valve and an air pump. A columnar supporting post has one end connected to the feeding pipe and another end connected to a weight sensor. The weight sensor firstly measures a dead weight of the feeding pipe, the columnar supporting post and the container and a net weight including the desired amount of the molten metal is assigned to the weight sensor. When the columnar supporting post is in contact with the weight sensor and the weight sensor measures a weight equal to the assigned net weight, the air pump begins to draw air into the container, thus guiding the molten metal out of the container.

[0006] The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing, in which:

BRIEF DESCRIPTION OF DRAWING

[0007]FIG. 1 is a schematic view of a prior art feeding sensor of quantitative control before loading molten metal into a die;

[0008]FIG. 2 is a schematic view of a prior art feeding sensor of quantitative control after loading molten metal into a die;

[0009]FIG. 3 is a schematic view of the feeding sensor of quantitative control of the present invention before loading molten metal into a die; and

[0010]FIG. 4 is a schematic view of the feeding sensor of quantitative control of the present invention after loading molten metal into a die.

DETAILED DESCRIPTION OF THE INVENTION

[0011]FIGS. 3 and 4 show the feeding sensor of quantitative control for a die caster according to the present invention. The feeding sensor of quantitative control comprises a storage tank 1 containing molten metal 2, a positioning member 4 atop the storage tank 1. A feeding pipe 3 passes through a top opening 11 of the storage tank 1 and with an inlet end thereof being below the surface of the molten metal. The feeding pipe 3 has a central bent portion fit with the positioning member 4. An outlet end of the feeding pipe 3 is connected to a container 7 of fixed volume. A columnar supporting post 5 is arranged below the feeding pipe 3 and connected to a weight sensor 6. The container 7 has a control valve 9 and an air pump 8. The weight sensor 6 firstly measures the total dead weight of the feeding pipe 3, the columnar supporting post 5 and the container 7. Moreover, a desired weight for the molten metal 2 is assigned. The air pump 8 initially drains air out of the container 7 such that the molten melt 2 continuously flows into the container 7 until the desired mount of the molten melt 2 is stored in the container 7. At this time, the air pump 8 stops draining air out of the container 7. Afterward, the control valve 9 guides the molten melt 2 with desired amount to a die of a caster.

[0012] The air pump 8 is used to establish a reduced pressure in the container 7 by draining air, whereby the molten metal 2 naturally flows from the storage tank 1 into the container 7. The components including the feeding pipe 3, the container 7 and the control valve 9 are pivoted at the positioning member 4, which is a movable shaft. As shown in FIG. 3, the positioning member 4 is firstly at a position such that the deadweight of the feeding pipe 3, the columnar supporting post 5 and the container 7 is loaded on the weight sensor 6. As the molten metal 2 flowing from the storage tank 1 into the container 7, the weight loading on the weight sensor 6 is increased. When the net weight is equal to the deadweight plus the desired amount of the molten metal 2, the weight sensor 6 commands the air pump 8 to stop draining air and begin to draw air into the container 7, as shown in FIG. 4. At this time, the control valve 9 is opened and the molten metal 2 smoothly flows into the container 7 due to increased pressure in the container 7. The molten metal 2 is loaded to the die of the caster through the control valve 9. The operation of the air pump 8 is controlled by the weight sensor 6. The weight of the container 7 is decreased due to the molten metal 2 loaded to the die of the caster. The positioning member 4 is moved to such a position that the columnar supporting post 5 is always in contact with the weight sensor 6. When the weight of the feeding pipe 3, the columnar supporting post 5 and the container 7 is returned to the deadweight, the weight sensor 6 commands the air pump to drain air out of the container 7. Therefore, the molten metal 2 can again flow into the container 7 for next die-casting.

[0013] Alternatively, the positioning member 4 can be omitted and the columnar supporting post 5 is directly in contact with the weight sensor 6. In this case, the components including the feeding pipe 3, the container 7 and the control valve 9 are pivoted at the weight sensor 6, wherein the weight sensor 6 can be a weight scale.

[0014] In the present invention, the total dead weight of the feeding pipe 3, the columnar supporting post 5 and the container 7 preferably includes the weight of the molten metal 2 remained in the feeding pipe 3. The remained molten metal 2 neither flows into the container 7 nor flows back to the storage tank 1. Therefore, the molten metal 2 remained in the feeding pipe 3 is not loaded in to the die for casting. The amount of the remained molten metal 2 should be taken account in the total dead weight to precisely measure the desired amount of the molten metal 2. The positioning member 4 is used to enhance the precision of measurement.

[0015] To sum up, the present invention uses a columnar supporting post connected to the feeding pipe. The molten metal is loaded to a die when a desired amount of molten metal is measured. Alternatively, the columnar supporting post can also be connected to the container (this case is not shown) to provide similar effect. In other word, the present invention uses an externally arranged weight scale instead of an internally arranged sensor stick. The sensing unit is arranged in exterior of the high-temperature container. The maintenance and the repair of the feeding sensor for quantitative control are easy.

[0016] Although the present invention has been described with reference to the preferred embodiment thereof, it will be understood that the invention is not limited to the details thereof. Various substitutions and modifications have suggested in the foregoing description, and other will occur to those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims. 

I claim
 1. A feeding sensor of quantitative control for die caster, comprising a storage tank used to store a molten metal and having an opening atop a top side thereof; a feeding pipe having one end passing through the opening of the storage tank and placed below a surface of the molten metal; a container of fixed volume, the container being connected to another end of the feeding pipe and having a control valve and an air pump, the air pump draining air out of the container whereby the molten metal flows into the container through the feeding pipe; a columnar supporting post having one end connected to the feeding pipe; and a weight sensor connected to another end of the columnar supporting post and being assigned with a net weight including the desired amount of the molten metal; when the columnar supporting post is in contact with the weight sensor and the weight sensor measuring a weight equal to the assigned net weight, the air pump begins to draw air into the container, thus guiding the molten metal out of the container.
 2. The feeding sensor of quantitative control for die caster as in claim 1, wherein a positioning member is provided atop the storage tank and the feeding pipe is connected to the positioning member.
 3. The feeding sensor of quantitative control for die caster as in claim 2, wherein the positioning member is a movable shaft.
 4. The feeding sensor of quantitative control for die caster as in claim 1, wherein the weight sensor is a weight scale.
 5. The feeding sensor of quantitative control for die caster as in claim 1, wherein the air pump is controlled by the weight sensor to drain or draw air.
 6. A feeding sensor of quantitative control for die caster, comprising a storage tank used to store a molten metal and having an opening atop a top side thereof; a feeding pipe having one end passing through the opening of the storage tank and placed below a surface of the molten metal; a container of fixed volume, the container being connected to another end of the feeding pipe and having a control valve and an air pump, the air pump draining air out of the container whereby the molten metal flows into the container through the feeding pipe; a columnar supporting post having one end connected to the container; and a weight sensor connected to another end of the columnar supporting post and being assigned with a net weight including a desired amount of the molten metal; when the columnar supporting post is in contact with the weight sensor and the weight sensor measuring a weight equal to the assigned net weight, the air pump begins to draw air into the container, thus guiding the molten metal out of the container.
 7. The feeding sensor of quantitative control for die caster as in claim 6, wherein a positioning member is provided atop the storage tank and the feeding pipe is connected to the positioning member.
 8. The feeding sensor of quantitative control for die caster as in claim 7, wherein the positioning member is a movable shaft.
 9. The feeding sensor of quantitative control for die caster as in claim 6, wherein the weight sensor is a weight scale.
 10. The feeding sensor of quantitative control for die caster as in claim 6, wherein the air pump is controlled by the weight sensor to drain or draw air. 